Alloy steel



l non-magnetic,

4'5 as compared with said prior steel.

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CHARLES MORRIS aormson, or AVALON, rmsYLvAmAif ALLOY STEEL. I

1,420,708. No Drawing.

To all whom it may concern:

.Be it known that 1, CHARLES MORRIS J oiIN- soN, residing at Avalon, in the county of Allegheny and State of Pennsylvania, a citi- 5 .zen of the United States, have invented ordiscovered certain new and usefulImprovements in Alloy Steel, of which improvements the following is a specification.

In a prior application filed by me on August 9th,.1920, Serial No. 401,656, I described a new alloy steel containing chro mium. nickel and silicon, which I- had found to be strongly resistant to high heat, to acids, and to rust, while at the same time being Stated generally, the said steel contained from about ten per cent to about twenty per cent of-chromium, from about nine per cent to about twenty-five per cent of nickel, and from about one per cent to about ten per cent of silicon, but it was considered perferably that the chromium and the nickel-should be contained in the steel in fairly equal proportions. Such steel, as is stated in the said application, was'very tough, and was consequently somewhat diiiicult to machine. I

In making further investigations with a view to enlarging the field of usefulness of the steel ofiny aforesaid application, I have discovered that a steel of this'type can be rendered easily machinable by changing the relative proportions of the chromium and nickel contents, that is to say by using nickel in amount substantially double the amount (if 85 chromium, or even greatly in-excess of double,.in some case's, whe're hardness is of. minor importance-the content of nickel may be even slxtimes' the chromium content,-- the silicon contentbeing in general subject 40 to the same variations asin the steel of my said prior application! This change in the relative proportions of the chromium and i nickel results in a lowering of the chromium limit and an increasing of the nickel limit, Thus in this, case the-chromium..-in the steel may range from about six per cent to about eighteenjpe'r cent, and the nickel from about twelve per cent to about thirty-six per cent, whilethesiliconacontentmay befrom about one per cent to about ten-per cent as before.

In any case the iron should be kept at a minimum of fifty per cent of the" product, in i I order to insure tensile strength and to-.obi-'. I

Within the above limits I have produced steel containing chromium from ten per cent to fifteen perjcent, .niekel, from thirty per cent to thirtyj-six per cent, silicon about four per cent, and carbon. from ,30 per cent to .50 per cent, which is'easily machinable, while Specification of Letters Patent. Patented J 11116 27, 1922- Applieation filed March 28,1921. Serial No. 456,191., 3 I

ta possessing toan extent suflicient for many purposes all of the resistant qualities of the steel of in said Jp'rior application. This steel, as wellas-that of my said prior appli cation, is of high 'electrical'resi'stance, and is therefore useful in varieties of electrical apparatus where that quality is desired,

1 It is a matter of common experience that nickel and: cobalt have many like chemical properties, and that the metallurgieiilef fects in alloy steels are generally alike, so I desire it'to be understood that in the appended claimsl intend to covertheuse of cobalt as a substitute for nickel in whole or;

in part. The steel may ofcourse contain the usual small quantities of Ipanganese, etc, v and other alloying elementsanay'also be em--. ployed without departure from the inven tion. p

I claim as my invention: j 1. Steelcontam ng from about six per cent to about eighteen per cent of chromium,

fromabout twelve per. cent to about thirtysix percent ofznickel, from about -one.;per i I cent'toflabouttenper cent of silicon, and at I least fifty'per cent'ofiron, -the content of nickel being substgg ti l e) e content of hiy not less than-fifty per cent of iron.

' Intestimony whereofl hav e hereunto set my han fWit'ness'eslz fMARSH ALL A. CHmsTY, -.FRANOIS J. TOMASSON.

2. Steel containing from steeper cent to fifteen per cent. of chromium, from thirty" per centto thirty-six per cent of nickel, from one percent to five per cent, of silicon, and 

